I am using the following Excel formula to get the relative row number for a calculation.

=$A9*(C3)

Cell C3 contains a constant value, so I always want to use that value, regardless of the row.
When I apply the function to the rows, the rows increment correctly, but Excel is also incrementing the C column to C4, then C5, then C6. I want the formula to always use the value in C3, regardless of the row, how do I force it to do that?